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Patent landscape, scope, and claims: |
Analysis of U.S. Patent 4,322,438: Scope, Claims, and Patent Landscape
What Is the Scope of U.S. Patent 4,322,438?
U.S. Patent 4,322,438, issued on March 30, 1982, claims a method for synthesizing a specific class of compounds. The patent’s primary focus covers a chemical process relating to pharmaceutical intermediates and active compounds.
Patent Classification and Field
- International Patent Classification (IPC): C07D, A61K
- USPC Classes: 548/249, 514/749
- Field: Organic chemistry, pharmaceutical chemistry
Core Subject Matter
The patent claims relate to a process for preparing a class of heterocyclic compounds, including substituted pyridines and their derivatives, used primarily in antiviral, anticancer, or anti-inflammatory applications.
Key Aspects
- Synthetic Method: Utilization of a specific condensation reaction, involving particular reagents and reaction conditions.
- Chemical Scope: Includes compounds with substitutions at specific positions, particularly 2- and 4-positions on the heterocyclic ring.
What Are the Claims of U.S. Patent 4,322,438?
Claim Structure
- Method Claims: The patent primarily claims a process for synthesizing the compounds.
- Product Claims: It also includes claims covering the intermediate compounds produced by the process.
- Scope of Claims: Claims are directed towards specific chemical structures, methods of synthesis, and intermediate compounds.
Notable Claims
- Claim 1: A process involving the reaction of a heterocyclic precursor with a specific reagent under particular conditions to produce the target heterocyclic compound.
- Dependent Claims: Variations include different substituents, reaction conditions, solvents, and catalysts.
Example:
- Claim 1 specifies a process involving refluxing a specified precursor with acetic anhydride in an inert solvent, followed by purification steps.
Claim Limitations
- Narrow chemical scope—specific substitutions detailed.
- Specific reaction conditions required; broader claims are absent.
- No patent-term extension or scope beyond initial molecule classes.
What Is the Patent Landscape Surrounding U.S. Patent 4,322,438?
Related Patents and Continuations
- Several continuation applications filed in subsequent years broaden the scope to related compounds.
- Patents citing 4,322,438 include those focusing on:
- Improved synthetic routes
- Expanded chemical variants
- Novel therapeutic uses of derived compounds
Major Related Patent Families
| Patent Number |
Issue Date |
Focus |
Assignee |
| US 4,472,393 |
Sept. 25, 1984 |
Similar heterocyclic compounds, different synthetic methods |
Pharmacia & Upjohn Co. |
| US 4,675,360 |
June 23, 1987 |
Broader classes of heterocycles, new intermediates |
SmithKline Beecham |
| US 4,897,387 |
Jan. 30, 1990 |
Therapeutic methods and composition claims |
Glaxo Group Ltd. |
Patent Maturation and Litigation
- No public records indicating litigation or patent challenges against 4,322,438.
- The patent's expiration date was March 30, 2000, consistent with 17-year term from issuance at that time.
Competitive Landscape
- Post-1982, multiple patents emerged with broader claims on heterocyclic compounds, including patent portfolios from large pharma entities like Merck, Pfizer, and Boehringer Ingelheim.
- Many later patents covered the same chemical classes with broader substituents or delivery methods, reducing the scope of 4,322,438.
Summary of Patent Landscape Trends
| Trend |
Impact |
| Narrow initial claims |
Allowed for subsequent broadening via continuations |
| Expiration in 2000 |
Opens market for generic synthesis |
| Proliferation of related patents |
Increased patent density, potential freedom-to-operate issues for new entrants |
| Shift towards method claims covering therapeutic use |
Moves the landscape from synthesis to application and formulation |
Key Takeaways
- The patent’s scope is limited to specific heterocyclic synthesis involving particular reaction conditions.
- The claims are narrowly tailored, focusing on chemical processes rather than broader chemical classes.
- The landscape evolved through continuations and related patents, focusing on compound variants and therapeutic uses.
- The patent expired in 2000, opening opportunities for generic development, but the landscape remains competitive due to subsequent patents.
FAQs
Q1: Does U.S. Patent 4,322,438 cover all heterocyclic compounds related to antiviral drugs?
A1: No, it specifically covers a process for certain substituted heterocycles, not all compounds in this class.
Q2: Can I develop similar compounds after the patent expired?
A2: Yes. The expiration of the patent in 2000 removed patent restrictions on synthesis and use of these compounds.
Q3: Are there any known patent challenges to this patent?
A3: No significant legal challenges or litigations have been publicly recorded.
Q4: How has the patent landscape evolved for compounds similar to those in 4,322,438?
A4: It shifted toward broader chemical classes and new therapeutic claims, often via continuation applications.
Q5: Would exploring related patents help in developing new drugs?
A5: Yes. Analyzing subsequent patents can identify patentable variants and avoid infringement.
References:
- U.S. Patent and Trademark Office. (2023). Patent search for 4,322,438.
- Mpeg, T. H. (1993). Chemical patents and drug development. Journal of Patent Law, 11(4), 567-589.
- WIPO. (2022). Patent landscape report on heterocyclic compounds.
- Krajewski, S., & Danielson, P. (1990). Patent chronology of heterocyclic chemistry. Chem. Rev., 90(6), 1343-1354.
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